<\/span><\/h2>\n\n\n\nN\u1ebfu b\u1ea1n c\u00f3 m\u1ed9t danh s\u00e1ch kh\u00e1 d\u00e0i c\u00e1c ch\u1ecdn l\u1ef1a, b\u1ea1n c\u00f3 th\u1ec3 mu\u1ed1n nh\u00f3m c\u00e1c ch\u1ecdn l\u1ef1a l\u1ea1i v\u1edbi nhau \u0111\u1ec3 ng\u01b0\u1eddi d\u00f9ng d\u1ec5 d\u00e0ng quan s\u00e1t v\u00e0 thao t\u00e1c. Khi \u1ea5y b\u1ea1n n\u00ean d\u00f9ng th\u1ebb optgroup. Code m\u1eabu:<\/p>\n\n\n\n
<select name=\"gianha\">\n<optgroup label=\"D\u01b0\u1edbi 500 tri\u1ec7u\">\n<option value=\"499\">499 tri\u1ec7u \u2013 60m2<\/option>\n<option value=\"350\">350 tri\u1ec7u \u2013 40m2<\/option>\n\n<option value=\"250\">250 tri\u1ec7u \u2013 25m2<\/option>\n<\/optgroup>\n\n<optgroup label=\"Tr\u00ean 500 tri\u1ec7u\">\n<option value=\"700\">700 tri\u1ec7u \u2013 85m2<\/option>\n<option value=\"900\">350 tri\u1ec7u \u2013 100m2<\/option>\n<option value=\"1200\">1.2 t\u1ef7 \u2013 150m2<\/option>\n<\/optgroup>\n<\/select><\/code><\/pre>\n\n\n\nK\u1ebft qu\u1ea3:<\/p>\n\n\n\n